A taxiing system installed on an aircraft makes it possible during stages when the aircraft is taxiing to move in a manner that is autonomous, i.e. avoiding making use of the main engines of the aircraft.
In an electrical taxiing system, wheels carried by one or more undercarriages are driven in rotation during stages of taxiing by actuators that include electric motors.
During stages of aircraft taxiing while using such a taxiing system, the aircraft is thus driven by the undercarriages that have wheels driven in rotation by the taxiing system.
It is important to control accurately the speed of such a taxiing system, in particular while maneuvering the aircraft (forwards or backwards) with an aircraft ground speed that is small.
Typically, for an aircraft ground speed of 2 knots (kt), the required accuracy is 10%, i.e. 0.2 kt, or about 10 centimeters per second (cm/s). Such accuracy is relatively complex to obtain, particularly since measurements of ground speed are subject to various sources of inaccuracy: inaccuracy of the sensor(s); data resolution; transmission delays; etc. The accuracy must also be robust in the face of large variations in the forces to which the taxiing system is subjected, given that the weight of the aircraft can vary over a range of one to two, and given that the effects of any slopes of the tracks on which the aircraft is taxiing are considerable.